Hey Coopz, did you know the SR4 comes with an e-gyro (electric gyro) in the back wheel, where the Himoto MX400 uses a mechanical gyro. Different in general between e-gyro and mech gyro is night and day. Egyro runs continuously so bike is stable entire time where a mech gyro requires you to have space to get the bike speed up for a few seconds as the back wheel gets the gyro inside spinning. I have not heard enough from owners of either bike to give you advice on one or another. One thing to consider is parts availability. The himoto you can get parts from what is it, NitroRCX I think, then Atomik is now selling himoto so they have some parts it appears. There is even another bike that's sort of new, the ZD Racing Phantom400, which is basically a re-release of the Quantum QRF400 that Hobbyking used to sell a couple years ago. Unfortunately no distributors for it, but that bike is based on the ARX540, so some parts are interchangeable. Its a shame Atomik abandoned the MM450 (now discontinued) or I would say that bike. After enjoying the e-gyro I can say I will never go back to a mech gyro unless Im seriously desperate, and I hope its never that bad. You could get the Himoto, then find the SR4 e-gyro with back wheel/swingarm maybe and Ive seen a youtube video of that so its doable if you want that option in the future.